I can totally empathize with you Frog. I work overseas for most of the year and was doing my training with John over an extended period whenever I returned to Aus. I had booked more training for before Xmas and was really looking forward to a few more flights with John.
I am currently in China and found out by chance that there had been a dual fatality in Rocky, I was in total shock and disbelief when I found out that John was one of those poor guys.
John was the most wonderful person, he was as you said - serious, thorough, safe - he never took me up on a day that was not perfect. There were days that he did not make any money because the weather was not quite right (although it seemed ok to me) and therefore we would only do theory lessons and chat.....he refused to accept money on those occasions.
It wasn't just his knowledge that made him a great instructor - it was his easy manner, patience and modesty - I felt totally safe and at ease with him.
I am not sure if I will continue my training elsewhere sometime in the future, because as many have said - if it can happen to John it can happen to anyone, but also - finding another instructor with John's qualities might be a big ask.
I know what John would say though - "get back up there....."